[gnuastro-commits] master dc67dc1 2/2: Library (wcs.h): new function to return WCS dimension name

[Mohammad Akhlaghi]

branch: master
commit dc67dc1706e71b2f7f426397bb1e12a8abd43cc9
Author: Mohammad Akhlaghi <mohammad@akhlaghi.org>
Commit: Mohammad Akhlaghi <mohammad@akhlaghi.org>

    Library (wcs.h): new function to return WCS dimension name
    
    In some contexts, it is useful to report the name of given WCS
    coordinates. With this commit, the new 'gal_wcs_dimension_name' will do the
    job.
---
 NEWS               |  3 +++
 bin/fits/fits.c    | 23 ++---------------------
 doc/gnuastro.texi  |  7 +++++++
 lib/gnuastro/wcs.h |  2 ++
 lib/wcs.c          | 28 ++++++++++++++++++++++++++++
 5 files changed, 42 insertions(+), 21 deletions(-)

diff --git a/NEWS b/NEWS
index 5a17b58..c509137 100644
--- a/NEWS
+++ b/NEWS
@@ -37,6 +37,9 @@ See the end of the file for license conditions.
      'astquery' option, to easily search the contents of external databases
      within the image.
 
+  Library:
+   - gal_wcs_dimension_name: return the name of the requested WCS dim.
+
 ** Removed features
 
 ** Changed features
diff --git a/bin/fits/fits.c b/bin/fits/fits.c
index eab09c5..ebd000e 100644
--- a/bin/fits/fits.c
+++ b/bin/fits/fits.c
@@ -353,25 +353,6 @@ fits_pixelscale(struct fitsparams *p)
 
 
 
-/* Extract the dimension name from CTYPE. */
-static char *
-fits_wcs_dim_name(char *ctype)
-{
-  size_t i;
-  char *out;
-
-  /* Make a copy of the CTYPE value and set the first occurance of '-' to
-     '\0', to avoid the projection type. */
-  gal_checkset_allocate_copy(ctype, &out);
-  for(i=0;i<strlen(out);++i) if(out[i]=='-') out[i]='\0';
-
-  /* Return the output array. */
-  return out;
-}
-
-
-
-
 
 static void
 fits_skycoverage(struct fitsparams *p)
@@ -531,8 +512,8 @@ fits_skycoverage(struct fitsparams *p)
       /* For the range type of coverage. */
       printf("\nSky coverage by range along dimensions:\n");
       for(i=0;i<ndim;++i)
-        printf("  %-8s %-15.10g%-15.10g\n",
-               fits_wcs_dim_name(wcs->ctype[i]), min[i], max[i]);
+        printf("  %-8s %-15.10g%-15.10g\n", gal_wcs_dimension_name(wcs, i),
+               min[i], max[i]);
     }
 
   /* Clean up. */
diff --git a/doc/gnuastro.texi b/doc/gnuastro.texi
index cb1c4b7..fe4143c 100644
--- a/doc/gnuastro.texi
+++ b/doc/gnuastro.texi
@@ -23045,6 +23045,13 @@ number of coordinate representations found into the 
space that @code{nwcs}
 points to. Please see @code{gal_wcs_read_fitsptr} for more.
 @end deftypefun
 
+
+@deftypefun {char *} gal_wcs_dimension_name (struct wcsprm @code{*wcs}, size_t 
@code{dimension})
+Return an allocated string array (that should be freed later) containing the 
first part of the @code{CTYPEi} FITS keyword (which contains the dimension name 
in the FITS standard).
+For example if @code{CTYPE1} is @code{RA---TAN}, the string that function 
returns will be @code{RA}.
+Recall that the second component of @code{CTYPEi} contains the type of 
projection.
+@end deftypefun
+
 @deftypefun void gal_wcs_write (struct wcsprm @code{*wcs}, char 
@code{*filename}, char @code{*extname}, gal_fits_list_key_t @code{*headers}, 
char @code{*program_string})
 Write the given WCS structure into the second extension of an empty FITS 
header.
 The first/primary extension will be empty like the default format of all 
Gnuastro outputs.
diff --git a/lib/gnuastro/wcs.h b/lib/gnuastro/wcs.h
index dede089..b4c0aac 100644
--- a/lib/gnuastro/wcs.h
+++ b/lib/gnuastro/wcs.h
@@ -85,6 +85,8 @@ struct wcsprm *
 gal_wcs_read(char *filename, char *hdu, size_t hstartwcs,
              size_t hendwcs, int *nwcs);
 
+char *
+gal_wcs_dimension_name(struct wcsprm *wcs, size_t dimension);
 
 
 
diff --git a/lib/wcs.c b/lib/wcs.c
index 93a1233..492eb64 100644
--- a/lib/wcs.c
+++ b/lib/wcs.c
@@ -41,6 +41,8 @@ along with Gnuastro. If not, see 
<http://www.gnu.org/licenses/>.
 #include <gnuastro/dimension.h>
 #include <gnuastro/permutation.h>
 
+#include <gnuastro-internal/checkset.h>
+
 #if GAL_CONFIG_HAVE_WCSLIB_DIS_H
 #include <wcslib/dis.h>
 #include <gnuastro-internal/wcsdistortion.h>
@@ -298,6 +300,32 @@ gal_wcs_read(char *filename, char *hdu, size_t hstartwcs,
 
 
 
+/* Extract the dimension name from CTYPE. */
+char *
+gal_wcs_dimension_name(struct wcsprm *wcs, size_t dimension)
+{
+  size_t i;
+  char *out;
+
+  /* Make sure a WCS pointer actually exists. */
+  if(wcs==NULL) return NULL;
+
+  /* Make sure the requested dimension is not larger than the number of
+     dimensions in the WCS. */
+  if(dimension >= wcs->naxis) return NULL;
+
+  /* Make a copy of the CTYPE value and set the first occurance of '-' to
+     '\0', to avoid the projection type. */
+  gal_checkset_allocate_copy(wcs->ctype[dimension], &out);
+  for(i=0;i<strlen(out);++i) if(out[i]=='-') out[i]='\0';
+
+  /* Return the output array. */
+  return out;
+}
+
+
+
+